1. Field of the Invention(s)
The present invention(s) relate to vehicle suspension systems; and more particularly, to vehicle suspension systems employing multi-part spring arrangements.
2. Background of the Invention(s)
Suspension systems for commercial vehicles of the type illustrated in FIG. 2 of the accompanying drawings are known. The configuration of the long spring member (PA), however, is not optimal. As an example, to facilitate construction of the monolithic spring member, it is made with a substantially uniform thickness as seen from the side view of FIG. 2, along the entire length. This construction, however, is significantly overbuilt resulting in unnecessary material cost, as well as needlessly adding weight to the incorporating vehicle.
In practice, the forward portion of the spring (PA), that is, the portion of the spring extending to the left-hand side of the axle assembly in FIG. 2, handles approximately ninety percent of the vertical forces imposed on the suspension arrangement during vehicle operation. This imbalance further supports the conclusion that the portion of the spring extending toward the air spring at the right-hand side of the axle assembly in FIG. 2 is drastically overbuilt. Moreover, the inclined portion of this part of the spring, because of the vertical distance over which it must extend and the clearance that must be provided about the axle assembly for proper operation, causes a greater horizontal extension of the distal end of the spring than performance requirements demand.
In view of these detrimental aspects of the traditional spring suspension design of FIG. 2, motivation exists for providing the same or better functionality, while at the same time reducing the overbuilt aspects of the spring.